Moments later, with pressure eased by the massive landslide, the mountain's northern face blew away, sending out lava and pulverized rock that would destroy nearly everything up to 19 miles away.

Lava continued to flow, one layer on top of another, for several minutes.

Meanwhile, ash shooting into the air was carried on winds and deposited as far away as Minnesota and New Mexico, with some of the ash traveling completely around the globe over the next two weeks.

As far away as Spokane, the ash blotted out the midday sun, reducing visibility to less than 10 feet and choking people who breathed in the ash.

The ash also caused lightning, which triggered forest fires.

Heat from the eruption melted glaciers on St. Helens' face, which in turn triggered lahars (volcanic mudflows) that found their way at least 27 miles downstream on the Toutle and Cowlitz rivers, all the way into the Columbia.

Earthquakes and smaller eruptions continued in the days after the initial eruption.

Pilot Jess Hagerman recalled landing a helicopter on a "dilapidated" bridge in a video reposted to Twitter by the Washington National Guard.

"That was kind of an interesting experience actually, because there wasn't quite room to land on the bridge," Hagerman said in the archival video. Hagerman set one skid on a log and then had his co-pilot hop out and move the log so he could land the chopper.

Aside from killing 57, the eruption destroyed 185 miles of highway, took out bridges, houses and other infrastructure, and killed all the wildlife in its path.

Forests were mowed down. Had it not been a Sunday, hundreds of Weyerhaeuser workers would have been in the forests at work, and thus also killed by the blast. In addition, residents in the area who had been evacuated several days before had been allowed back in to collect personal belongings just the day before.

Trees felled by the landslide and then the lava flows still float on the surface of Spirit Lake below the volcano.

Thirty-eight years on, the landscape remains vastly different. Photos show that trees have not returned to areas close to the mountain, where once stood a sea of green. And the ash- and lahar-covered landscape still looks more reminiscent of the moon than the Earth, even if it has some signs of life showing through.